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<title>rename</title>
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<h2 align=center>rename</h2>
<h4 align=center>OS/161 Reference Manual</h4>

<h3>Name</h3>
rename - rename or move a file

<h3>Library</h3>
Standard C Library (libc, -lc)

<h3>Synopsis</h3>
#include &lt;unistd.h&gt;<br>
<br>
int<br>
rename(const char *<em>oldname</em>, const char *<em>newname</em>);

<h3>Description</h3>

The file (or other object) referenced by <em>oldname</em> is given the
name <em>newname</em>, and the name <em>oldname</em> is removed. If
<em>newname</em> already exists, it is removed as well. (The semantics
for removing files and directories described under 
<A HREF=remove.html>remove</A> and <A HREF=rmdir.html>rmdir</A>
must be honored.)
<p>

If <em>newname</em> exists, it must be a directory if and only if
<em>oldname</em> also is.
<p>

If components of the path prefix of <em>newname</em> do not exist or
are not directories, rename fails. Additionally, <em>oldname</em> and
<em>newname</em> must refer to names on the same filesystem.
<p>

If <em>oldname</em> and <em>newname</em> are the same file, rename
succeeds and the state of the filesystem is not altered.
<p>

Rename must be atomic; no other process on the system should be able
to see the filesystem in a state where both (or neither)
<em>oldname</em> and <em>newname</em> name the file. Additionally, if
the system crashes, at least one name for the file must remain.
<p>

If <em>oldname</em> is a directory, <em>newname</em> must not refer to
a subdirectory of <em>oldname</em>, as this would create a cycle in the
directory tree.
<p>

Renaming the "." or ".." entries in directories is prohibited.
<p>

<h3>Return Values</h3>
On success, rename returns 0. On error, -1 is returned, and
<A HREF=errno.html>errno</A> is set according to the error
encountered.

<h3>Errors</h3>

The following error codes should be returned under the conditions
given. Other error codes may be returned for other errors not
mentioned here.

<blockquote><table width=90%>
<td width=10%>&nbsp;</td><td>&nbsp;</td></tr>
<tr><td>ENODEV</td>		<td>The device prefix of one of the names did
				not exist.</td></tr>
<tr><td>ENOTDIR</td>	<td>A non-final component of one of the names
				was not a directory.</td></tr>
<tr><td>ENOENT</td>		<td>A non-final component of <em>newname</em>   
				did not exist.</td></tr>
<tr><td>ENOENT</td>		<td><em>oldname</em> does not exist.</td></tr>
<tr><td>ENOTDIR</td>	<td><em>oldname</em> is a directory, and 
				<em>newname</em> is not.</td></tr>
<tr><td>EISDIR</td>		<td><em>oldname</em> is not a directory, and 
				<em>newname</em> is.</td></tr>
<tr><td>ENOTEMPTY</td>	<td><em>newname</em> is a directory, and it is
				not empty.</td>   
<tr><td>EXDEV</td>		<td>The two names are on different filesystems.</td></tr>
<tr><td>EINVAL</td>		<td><em>newname</em> is a subdirectory of
				<em>oldname</em>.</td></tr>
<tr><td>EINVAL</td>		<td>An attempt was made to rename "."</td></tr>
<tr><td>ENOSPC</td>		<td>The filesystem involved is full.</td></tr>
<tr><td>EIO</td>		<td>A hard I/O error occurred.</td></tr>
<tr><td>EFAULT</td>		<td>One of the arguments was an invalid pointer.</td></tr>

</table></blockquote>

As with rmdir, attempts to rename ".." may generate either EINVAL or
ENOTEMPTY. 

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